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From "Mario Wenzel (JIRA)" <j...@apache.org>
Subject [jira] [Created] (MATH-1397) Complex.ZERO.pow(2.0) is NaN
Date Mon, 21 Nov 2016 17:16:58 GMT
Mario Wenzel created MATH-1397:
----------------------------------

             Summary: Complex.ZERO.pow(2.0) is NaN
                 Key: MATH-1397
                 URL: https://issues.apache.org/jira/browse/MATH-1397
             Project: Commons Math
          Issue Type: Bug
    Affects Versions: 3.6.1
         Environment: Linux, Java1.7/Java1.8
            Reporter: Mario Wenzel
            Priority: Minor


```
package complextest;

import org.apache.commons.math3.complex.Complex;

public class T {
	public static void main(String[] args) {
		System.out.println(Complex.ZERO.pow(2.0));
	}
}
```

This is the code and the readout is `(NaN, NaN)`. This surely isn't right. For one, it should
actually be zero (https://www.wolframalpha.com/input/?i=(0%2B0i)%5E2) and second of all, the
documentation doesn't state that anything could go wrong from a Complex number that has no
NaNs and Infs.

The other definition states that it doesn't work when the base is Zero, but it surely should.
This strange corner case destroys any naive implementation of stuff wrt the mandelbrot set.

It would be nice to not have to implement this exception myself.



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